11661121 has 2 divisors, whose sum is σ = 11661122. Its totient is φ = 11661120.

The previous prime is 11661119. The next prime is 11661151. The reversal of 11661121 is 12116611.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11155600 + 505521 = 3340^2 + 711^2 .

It is a cyclic number.

It is not a de Polignac number, because 11661121 - 2¹ = 11661119 is a prime.

Together with 11661119, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (11661101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5830560 + 5830561.

It is an arithmetic number, because the mean of its divisors is an integer number (5830561).

Almost surely, 2^11661121 is an apocalyptic number.

It is an amenable number.

11661121 is a deficient number, since it is larger than the sum of its proper divisors (1).

11661121 is an equidigital number, since it uses as much as digits as its factorization.

11661121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72, while the sum is 19.

The square root of 11661121 is about 3414.8383563501. The cubic root of 11661121 is about 226.7671284297.

Adding to 11661121 its reverse (12116611), we get a palindrome (23777732).

The spelling of 11661121 in words is "eleven million, six hundred sixty-one thousand, one hundred twenty-one".